This invention relates to fluid filters, and more particularly to fuel filters for vehicles.
Many types of filters (also referred to as xe2x80x9cseparatorsxe2x80x9d) are known in the prior art. Filters are widely known for removing contaminants and other impurities from fluids such as fuel and oil. A popular type of filter has a housing that encloses a replaceable ring-shaped filter element. The filter element ensures that impurities are removed from fuel or oil before it is delivered to system components such as fuel injection pumps and fuel injectors. Mating portions of the housing form an interior enclosure for the element, and the housing portions may be separated for replacement of a spent filter element. Periodic replacement of the filter element is required so that the filter element will not become so loaded with impurities that flow is restricted. It is known that problems may arise when such filter elements are replaced.
One problem is that filter elements with different sizes and/or filtration capabilities often have identical mounting configurations and can fit on the same filter head. However, use of the wrong filter element can cause poor engine performance and allow undesirable amounts of contaminants to pass through the system.
Another problem is that individuals may remove a spent filter element and simply re-attach the housing portions without a fresh element. If an automatic drain valve is used in the filter (see, e.g., U.S. Pat. No. 5,468,386), fuel or oil can be dumped to drain when an element is not installed in the housing. While the engine may operate (at least for a short period of time), this can be detrimental to the engine, particularly if the operation of the engine depends on the continued supply of oil or fuel from the filter.
A still further problem is that upon removing the element, an individual may come into contact with the fuel/oil and any impurities on the element, and get dirty hands. The user typically has to reach down into the housing to grasp the element, and may come into contact with residual fuel or oil in the housing and on the element. In addition, any fuel or oil remaining on the element may drip off on the surrounding engine components when the element is removed, thereby fouling the engine; or worse yet, drip off onto the ground and create environmental issues.
To reduce and at least partially eliminate some of these problems, the filter assembly shown in U.S. Pat. No. 4,836,923, owned by the Assignee of the present application, was developed. This filter assembly includes a unique replaceable filter element that is attached to a removable cover. The filter element includes an opening in one end cap opposite from the cover, which allows the filter element to be removeably located over an elongated standpipe in the housing. The element is removed when the cover is removed (screwed off) from the housing. While this reduces skin contact with the element and thereby reduces the mess associated with an element change, this does not fully address the problem with fuel, oil and impurities draining off the element as it is removed from the housing and carried across the engine.
In addition, the cover of the housing in the ""923 patent is typically discarded with each spent element. This is undesirable from a conservation and solid waste standpoint, as the cover is usually a heavy plastic or metal component. It is generally desirable to minimize the amount of material discarded, particularly if a discarded element must be treated as hazardous waste and/or cannot be easily incinerated. The cover also represents a portion of the cost of the replacement element. As a result, this design adds cost to the replacement element.
The element in the ""923 patent may also be separated from the cover, and the cover re-attached to the housing without a fresh element also being installed. As such, this design does not fully address the problems associated with operating an engine without a filter element installed.
An improved filter assembly is shown in U.S. Pat. No. 5,770,065, also owned by the assignee of the present application. In this patent, a standpipe is similarly provided internally to the housing, and a spring-biased valve element is provided internal to the standpipe. The valve element is normally closed, and can be engaged and moved to an open position by a projection on an end cap of the element when the element is properly installed in the housing. The valve (and hence the filter assembly) generally cannot be operated without a proper filter element installed. The filter shown in the ""065 patent overcomes some of the problems associated with the earlier ""923 patent, however, the cover is attached to the element in the same manner as in the ""923 patent, and fuel and oil can still drip onto the engine and the surrounding area when the filter element is replaced. Also, as in the ""923 patent, the cover may be detached from the element and screwed back onto the housing with out a fresh element being installed. In some high-pressure fuel systems, the valve element may actually be forced open, and unfiltered fuel can be allowed to pass to the downstream components. This can also be detrimental to the engine.
It is therefor believed there exists a need for a still further filter that reduces if not eliminates, the mess and environmental issues associated with changing an element; and prevents the operation of the filter without a proper filter element.
A new and unique filter assembly is provided that prevents an improper filter element from being used in the filter and prevents operation of the filter without a filter element in place. Mess and environmental issues are substantially reduced, if not eliminated, during an element change. The filter element is also simple and low-cost to manufacture.
According to the present invention, the filter assembly includes a replaceable element with a ring of filtration media, and an end cap sealingly bonded to either end of the filtration media. An internal support core is fixed to an end wall of the filter housing, and one of the end caps of the filter element include a central opening, such that the filter element can be removably received over the support core. The support core provides internal support for the filter element, so that the filter element can be composed of only material which is easily incinerated.
An extension and locking assembly is provided with the support core. The extension and locking assembly operates to prevent the cover of the housing from being attached to the housing body without a proper filter element installed in the housing, or without a filter element in the housing. The extension and locking assembly includes a bypass member and a locking member. The bypass member is closely and slideably received in the locking member, while the locking member is closely and slideably received in the support core. In one embodiment, both the locking member and the bypass member have enlarged heads, with the enlarged head of the bypass member overlying the enlarged head of the locking member. A main spring extends between a shoulder on the support core and the enlarged head of the locking member to bias the locking member and bypass member outwardly from the support core.
When the locking member and bypass member are in their outer position, the distal inner end of the locking member urges the distal inner end of the bypass member radially outward against the inner surface of the support core. The support core includes an annular step or shoulder along its inner surface, and the distal inner end of the bypass member engages the step to prevent the extension and locking assembly from being pushed inwardly into the support core. The extension and locking assembly is long enough such that the cover of the housing cannot be attached to the housing body when the extension and locking assembly is in its outer position.
The enlarged head of the bypass member includes a series of openings which allow access to the enlarged head of the locking member. The openings are strategically placed, and the other end cap (opposite from the end cap of the filter element with the central opening) has a series of protrusions that extend axially inward from the end cap, in orientation with the openings. When the element is installed over the support core, the protrusions extend through the openings in the head of the bypass member and engage the head of the locking member. The protrusions force the locking member axially inward, and in so doing, move the distal inner end of the locking member away from the distal inner end of the bypass member. This allows the distal inner end of the bypass member to disengage from the step in the support core, and the locking member and bypass member to slide inwardly (retract) into the support core. In its inner position, the extension and locking assembly allows the filter element to be properly located in the filter housing, and the cover to be attached to the housing body.
As should be appreciated, a filter element without a correct arrangement of protrusions on its end cap will not engage the head of the locking member, and the extension and locking assembly will remain locking in its outer position, thereby preventing the filter element from being properly assembled in the filter housing.
Another feature of the filter assembly is that during an element change, when the cover is removed, the extension and locking assembly will urge the spent element slightly outwardly from the housing, as the extension and locking assembly moves to its outer position. This facilitates removing the spent filter element from the housing, and reduces contact with any fuel or oil remaining in the housing.
A bypass valve can be provided in the bypass member to allow fluid to bypass the filter element when the filter element becomes clogged with impurities. The bypass valve can be provided as a unitary piece with the bypass member, or as a separate piece supported by the bypass member. A bypass spring biases the head of the bypass valve against a central opening in the adjacent end cap to normally prevent fluid bypassing the element, but to allow fluid bypass when the pressure in the housing increases above a predetermined amount.
As discussed above, the filter element includes a pair of end caps, with a first of the end caps including a central opening to receive the central support core. The second end cap includes the protrusions for operating the extension and locking assembly, and can include a central opening if the bypass valve is used. The central opening in the second end cap is preferably bounded by a short annular flange, which extends inwardly into the filter element, and seals against the bypass valve when the element is located in the housing. The flange and protrusions can be easily formed with the end cap such as by molding the end cap as a unitary component, and the filter element is otherwise a simple and inexpensive component to manufacture. While not as preferred, the protrusions could also be formed on a separate piece and held against the inside surface of the second end cap.
Another feature of the present invention is that the filter element is preferably stored for shipment in a fluid-tight container. The container includes a cup-shaped body and a lid, with the lid being easily attachable to the body to allow easy access to the filter element. The body and lid are preferably formed from inexpensive, lightweight, incineratable material, for example, a plastic. The container body includes a retaining device, such as a ridge or bead, integral with either the sidewall and/or end wall of the body, which is designed to engage an appropriate part of the element and retain the element in the body. The retaining device can have a number of different forms, and can be configured to engage different locations on the filter element to retain the element within the container body. It is preferred that the retaining device be resilient, and resiliently deflect to engage a portion of the end cap, such as the outer periphery of one of the end caps.
During an element change, a fresh element can be removed from the container and set aside. The empty body of the container is then inverted, and inserted open-end first into the open end of the filter housing, in surrounding relation to the spent element. This is facilitated by the element sitting slightly outwardly from the housing as discussed above. The resilient retaining device engages the element, and cooperates with the element to retain the element to the body. The container body is then removed from the housing, with the element attached thereto. Upon removing the body from the housing, the body is immediately turned upright, thereby preventing any fuel or oil from dripping off the element and contaminating the surrounding area. The lid is then attached to the body, and the entire assembly, with the spent element, can then be disposed of such as by incineration.
Thus, as described above, the filter of the present invention prevents an improper filter element from being used in the filter, and prevents operation of the filter without a filter element in place. Mess and environmental issues are substantially reduced, if not eliminated, during an element change. The filter element is also simple and low-cost to manufacture.
Further features and advantages will be apparent upon reviewing the following Detailed Description of the Preferred Embodiment and the accompanying Drawings.